As computing technology continues to advance, computing devices with new form factors are introduced into the marketplace. These new form factors often provide users with new ways of computer-human interaction. For example, a large number of computing devices introduced in recent years have display screens that are also used for data entry. For example, personal digital assistants (PDAs) and tablet personal computers (PCs) typically have displays screens that function both as displays and as digitizers for receiving data.
Many existing screen input and navigation technologies are based on touch screen technology. A touch screen is a computer display screen that is sensitive to touch, for example, touching a stylus to the touch screen. In order to provide screen input and navigation functionality, touch screens are specially constructed screens. Current touch screen technology includes resistive, capacitive, and surface acoustic sensing touch screen panels. Specifically, touch screens may require special membranes, transparent conductive films, and large source and sensor arrays in addition to standard display manufacturing.
There are several drawbacks to requiring a touch screen for providing data input and navigation of a PDA or a tablet PC. Touch screens are typically expensive to manufacture, due to the sensitivity of the components. The cost of a touch screen increases dramatically as the size increases. Furthermore, current touch screen technology is typically only applied to build special displays and cannot readily retrofit existing monitors. Touch screens are also very sensitive to contamination during operation, which can lead to in costly repairs and to computer system downtime.